1. Technical Field
This invention relates to a structure for improving the ballistic performance of a telescoped ammunition round.
2. Background Art
Telescoped ammunition includes a propellant charge having an axial bore or cavity, a projectile housed entirely within the axial bore of the propellant charge and a case around the propellant charge. When a telescoped round of ammunition is loaded into the chamber of the gun, the projectile, being housed in a propellant charge, is not seated in the barrel of the gun as is the projectile of a round of conventional ammunition when in a gun chamber. When the telescoped round is fired, the projectile is forced forward into the barrel of the gun and becomes seated in the barrel. The firing force is also applied as an outward force to the case and may cause deformation or deflection of the case. After firing, it is desired to remove the remaining portions of the ammunition round from the gun chamber. Any resulting interference between the case and the chamber to such removal is undesirable.
It is known that a solid tubular steel case may lock in the chamber during firing and thus cannot be used when it is desired to have multiple firings of telescoped ammunition. It is also known to use a plastic case in an automatic fixture for telescoped ammunition. However, plastic is not capable of handling the ballistic cycle loads throughout a typical firing environmental temperature range of -65.degree. F. to +165.degree. F. without failing.
Further, it is known to fabricate a case from two sections which are then bonded together. For example, U.S. Pat. No. 3,892,181 issued to Goldin teaches a flat telescoped cartridge case which is formed of two separate, identical pieces which are joined by ultrasonic welding. As a result, such a fabricated case has the same disadvantages as a single piece case in that it may deform.
A single piece case with a single split is also known. Such a case can be extracted rearwardly from the chamber. However, the firing of the ammunition round may cause sufficient deflection and subsequent deformation of the case so as to prevent rapid and easy removal of the case. Such quick removal is a very desirable feature in a rapid fire system with automatic loading and unloading.
It would be desirable to develop a case which can operate over a wide temperature range without failure, does not deform during firing and can be reused. These are some of the problems this invention overcomes.